Multi-stage transmission

ABSTRACT

The multi-stage transmission comprises a drive input shaft and a drive output shaft, three single-web planetary gearset assemblies (P 1 , P 2 , P 3 ), at least six rotatable shafts ( 0, 1, 2, 3, 4, 5, 6 ) and at least five shift elements ( 03, 04, 13, 15, 16 ) so that six forward gears and one reverse gear can be engaged, such that the drive input shaft ( 1 ) is connected to the solar gear wheel or to the web of the first planetary gearset (P 1 ) via the clutch ( 15 ), the web or the solar gear wheel of the first planetary gearset (P 1 ) is in rotationally fixed connection with the housing, the drive output takes place via a shaft ( 2 ) which is connected to the annular gear wheel of the second planetary gearset (P 2 ) and to the web of the third planetary gearset (P 3 ), a shaft ( 3 ) is permanently connected to the web of the second planetary gearset (P 2 ) and to the annular gear wheel of the third planetary gearset (P 3 ), and a shaft ( 4 ) is permanently connected to the solar gear wheel of the second planetary gearset (P 2 ) and to the annular gear wheel of the first planetary gearset (P 1 ). A shaft ( 5 ) is permanently connected to the solar gear wheel or web of the first planetary gearset (P 1 ) and a shaft ( 6 ) is permanently connected to the solar gear wheel of the third planetary gearset (P 3 ). The planetary gearset assemblies (P 1 , P 2 , P 3 ) are coupled by means of shafts ( 0, 1, 2, 3, 4, 5, 6 ) and shift elements ( 03, 04, 13, 15, 16 ).

[0001] The present invention concerns a multi-stage transmission ofplanetary structure, in particular an automatic transmission for a motorvehicle, according to the preamble of claim 1.

[0002] Automatic transmissions of the prior art, in particular for motorvehicles, comprise planetary gearset assemblies which are engaged bymeans of frictional or shift elements such as clutches and brakes andare usually connected to a starting element such as a hydrodynamictorque converter or a fluid clutch that can operate with some slippingaction and is optionally provided with a bridging clutch.

[0003] Such a transmission is described in EP 0 434 525 A1. It comprisesessentially a drive input shaft and a drive output shaft arrangedparallel to one another, a dual planetary gearset assembly concentric tothe drive output shaft, and five shift elements in the form of threeclutches and two brakes, whose selective engagement, two at a time,determines the various gear transmission ratios between the drive inputand drive output shafts.

[0004] Furthermore, from DE 199 495 07 A1 by the present applicant amulti-stage transmission is known, in which two non-shifting maingearset combinations are provided, which produce two rotation speeds onthe output side which, besides the speed of the drive input shaft, canoptionally be engaged with a shiftable dual planetary gearset assemblythat acts on the drive output shaft, by selectively closing the shiftelements used in such manner that to shift from one gear to therespective next gear up or down, only one shift element of the two shiftelements actuated at the time has to be engaged or disengaged.

[0005] In addition, within the scope of EP 0 434 525 A1 a multi-stagetransmission is disclosed, which contains a drive input shaft and adrive output shaft arranged in a housing, a planetary gearset assemblyarranged concentrically with the drive output shaft consisting of fourelements denoted as from the first to the fourth in the order of theirspeed, i.e. a so-termed double planetary gearset assembly, and fiveshift elements, namely three clutches and two brakes, whose selectiveactuation in pairs determines various transmission ratios between thedrive input and drive output shafts, such that the transmission has twopower paths which enable six forward gears to be engaged by theselective actuation of the five shift elements two at a time.

[0006] The purpose of the present invention is to propose a multi-stagetransmission of the type described at the start, in which the structuralelaboration is optimised and, in addition, the efficiency in the maingears is improved in relation to slippage and gearing losses.

[0007] According to the invention this objective is achieved by thecharacterizing features of the independent claims 1 and 2. Advantagesand further advantageous design features emerge from the subordinateclaims.

[0008] According to the invention, the multi-stage transmission ofplanetary structure comprises a drive input shaft and a drive outputshaft arranged in a housing, at least three single-web planetary gearsetassemblies, the first single-web planetary gearset assembly defining afixed input transmission ratio for the second planetary gearset, atleast six rotating shafts and at least five shift elements, preferablytwo brakes and three clutches or three brakes and two clutches, whoseselective engagement in pairs produces various transmission ratiosbetween the drive input and the drive output shafts, so that preferablysix forward gears and one reverse gear can be engaged.

[0009] In this case the drive output is via a shaft connected to theannular gear wheel of the second planetary gearset and to the web of thethird planetary gearset, a further, third shaft being permanentlyconnected to the web of the second planetary gearset and to the annulargear wheel of the third planetary gearset, and a further, fourth shaftbeing permanently connected to the solar gear wheel of the secondplanetary gearset and to the annular gear wheel of the first planetarygearset; another shaft is permanently connected to the solar gear wheelof the third planetary gearset.

[0010] In a first preferred embodiment comprising two brakes and threeclutches, the drive input shaft is also connected via a clutch to thesolar gear wheel and to the web of the first planetary gearset and theweb or the solar gear wheel of the first planetary gearset is inrotationally fixed connection with the housing. In addition, a shaft ispermanently connected to the solar gear wheel or to the web of the firstplanetary gearset.

[0011] According to the invention a second embodiment is proposed, whichcontains three brakes and two clutches and in which the drive inputshaft is connected directly to the solar gear wheel or web of the firstplanetary gearset, the web or solar gear wheel of the first planetarygearset can be put in rotationally fixed connection with or releasedfrom the housing via a brake, and a shaft is permanently connected tothe web or solar gear wheel of the first planetary gearset.

[0012] In this case the planetary gearset assemblies are coupled bymeans of shift elements and/or shafts; preferably, the first planetarygearset is made as a positive planetary gearset and the second and thirdplanetary gearset as negative planetary gear sets.

[0013] Thanks to the construction according to the invention, suitabletransmission ratios and a considerable increase of the overall spread ofthe multi-stage transmission are obtained, which results in increaseddriving comfort and a significant reduction of fuel consumption.

[0014] The multi-stage transmission according to the invention issuitable for any motor vehicle, in particular for passenger cars andgoods vehicles such as trucks, buses, construction industry vehicles,rail vehicles, caterpillar track vehicles and suchlike.

[0015] Moreover, with the multi-stage transmission according to theinvention, the structural elaboration is reduced considerably by havinga small number of shift elements, namely preferably only three clutchesand two brakes or two clutches and three brakes.

[0016] Advantageously, the multi-stage transmission according to theinvention makes it possible to start up with a hydrodynamic converter,an external starting clutch or even some other suitable externalstarting element. It is also conceivable to enable a starting processwith a starting element integrated in the transmission. Furthermore, themulti-stage transmission according to the invention operates with highefficiency in relation to slippage and gearing losses.

[0017] In addition, the torques in the shift elements and even in theplanetary gearset assemblies are small. This reduces wear in themulti-stage transmission in a particularly advantageous way. Owing tothe low torques in the shift elements and planetary gearset assembliesthe transmission can be made smaller, which optimises the use ofstructural space and leads to cost reduction.

[0018] Furthermore, the transmission according to the invention isdesigned to allow adaptability to various drive train designs, both inthe force-flow direction and from the standpoint of space.

[0019] Below, the invention is explained in greater detail withreference to the drawings, which show:

[0020]FIG. 1 is a schematic view of an example embodiment of amulti-stage transmission according to the invention;

[0021]FIG. 2 is a schematic view of a second example embodiment of amulti-stage transmission according to the invention;

[0022]FIG. 3 is a schematic view of a third example embodiment of amulti-stage transmission according to the invention;

[0023]FIG. 4 is a schematic view of a fourth example embodiment of amulti-stage transmission according to the invention; and

[0024]FIG. 5 is a shift scheme for the multi-stage transmissionaccording to the invention, as illustrated in FIGS. 1, 2, 3 and 4.

[0025] According to FIGS. 1, 2, 3 and 4 the multi-stage transmission ofplanetary structure according to the invention comprises a drive inputshaft 1 (An) and a drive output shaft 2 (Ab), which are arranged in ahousing, and three single-web planetary gearset assemblies P1, P2 andP3, of which the first single-web planetary gearset P1 is preferablymade as a positive planetary gearset. The planetary gearset assembliesP2 and P3 are preferably made as negative planetary gear sets. Inaddition, six rotating shafts 1, 2, 3, 4, 5 and 6 and five shiftelements, namely three brakes 03, 04, 05 and two clutches 13, 16 (FIGS.1 and 2), or two brakes 03, 04 and three clutches 13, 15, 16 (FIGS. 3and 4) are provided, whose selective actuation two at a time bringsabout various transmission ratios between the drive input shaft 1 andthe drive output shaft 2, so that six forward gears and one reverse gearcan be engaged.

[0026] As can be seen from FIG. 1, the drive input shaft 1 is connecteddirectly to the solar gear wheel of the first planetary gearset P1 andthe web of the first planetary gearset P1 can be put in rotationallyfixed connection with, or released from the housing by means of a brake05. According to the invention, the drive output shaft 2 is connected tothe annular gear wheel of the second planetary gearset P2 and to the webof the third planetary gearset P3, and the shaft 3 is permanentlyconnected to the web of the second planetary gearset P2 and to theannular gear wheel of the third planetary gearset P3. Further, the shaft4 is permanently connected to the solar gear wheel of the secondplanetary gearset P2 and to the annular gear wheel of the firstplanetary gearset P1, while the shaft 5 is permanently connected to theweb of the first planetary gearset P1 and the shaft 6 permanently to thesolar gear wheel of the third planetary gearset P3.

[0027] According to the invention, the shafts 3 and 4 can be coupled tothe housing by the brakes 03 and 04 respectively; the clutch 13 connectsthe shafts 1 and 3 to or releases them from one another, and the clutch16 connects the shafts 1 and 6 to or releases them from one another,while the brake 05 connects the shaft 5 to the housing or releases ittherefrom.

[0028] The embodiment shown in FIG. 2 differs from the embodimentaccording to FIG. 1 in that the drive input shaft 1 is connecteddirectly to the web of the first planetary gearset (P1), the solar gearwheel of the first planetary gearset P1 can be connected to or releasedfrom the housing by means of a brake 05, and the shaft 5 is permanentlyconnected to the solar gear wheel of the first planetary gearset P1.

[0029]FIGS. 3 and 4 describe example embodiments of a multi-stagetransmission according to the invention, which have three clutches 13,15, 16 and two brakes 03, 04.

[0030] In FIG. 3 the drive input shaft 1 is connected via the clutch 15to the solar gear wheel of the first planetary gearset P1 and the web ofthe first planetary gearset P1 is in rotationally fixed connection withthe housing (shaft 0). According to the invention, the drive outputshaft 2 is connected to the annular gear wheel of the second planetarygearset P2 and to the web of the third planetary gearset P3, and theshaft 3 is permanently connected to the web of the second planetarygearset P2 and to the annular gear wheel of the third planetary gearsetP3. As can be seen from FIG. 3, the shaft 4 is permanently connected tothe solar gear wheel of the second planetary gearset P2 and to theannular gear wheel of the first planetary gearset P1, the shaft 5 ispermanently connected to the solar gear wheel of the first planetarygearset P1, and the shaft 6 permanently to the solar gear wheel of thethird planetary gearset P3.

[0031] Further, the shaft 3 can be coupled to the housing via the brake03 and the shaft 4 can be coupled to the housing via the brake 04, theclutch 13 connects the shafts 1 and 3 to or releases them from oneanother, the clutch 16 connects the shafts 1 and 6 to or releases themfrom one another, and the clutch 15 connects the shafts 1 and 5 to orreleases them from one another.

[0032] The embodiment shown in FIG. 4 differs from that of FIG. 3 inthat the drive input shaft 1 is connected via the clutch 15 to the webof the first planetary gearset P1, the solar gear wheel of the firstplanetary gearset P1 is in rotationally fixed connection with thehousing (shaft 0), and the shaft 5 is permanently connected to the webof the first planetary gearset P1.

[0033] In other embodiments the fixed connection of the web (FIG. 3) orthe solar gear wheel (FIG. 4 of the first planetary gearset P1 to thehousing can be replaced by a releasable connection, for example a brake.

[0034] This enables an electric motor or other suitable additional drivesource to be arranged on the shaft 0 released by means of the brake.

[0035] The corresponding shift scheme of the example embodimentsdiscussed above is the object of FIG. 5, in which, as examples,transmission ratios i and the resulting speed transitions φ are alsoindicated.

[0036] As shown, the multi-stage transmission according to the inventionhas a progressive gear variation. Furthermore, when shiftingsequentially double-shifts are avoided, since two neighboring gears ineach case use only one common shift element. Furthermore, any desiredshift between the first and fourth gear and between the fourth and thesixth gear involves the actuation of only one shift element. In theembodiments of FIGS. 1 and 2, for gears 1 to 4 the clutch 16 ispermanently actuated; these gears are engaged by the additionalactuation of the brake 03 (first gear), the brake 04 (second gear), thebrake 05 (third gear) and the clutch 13 (fourth gear). For gears 4 to 6,the clutch 13 remains closed and the gears are engaged by the additionalactuation of the brake 05 (fifth gear) and the brake 04 (sixth gear).According to the invention, engaging the reverse gear requires theactuation of the brakes 03 and 05.

[0037] The shift scheme for the embodiments of FIGS. 3 and 4 isanalogous, with the difference that instead of the brake 05, the clutch15 is actuated.

[0038] According to the invention, at any suitable point in themulti-stage transmission additional freewheels can be provided, forexample between a shaft and the housing or in order to divide or toconnect a shaft.

[0039] In addition, thanks to the structure according to the inventionthe drive input and output shafts can be arranged either on the sameside of the transmission or on opposite sides. In addition, an axledifferential or a transfer differential can also be arranged on thedrive input or drive output of the transmission.

[0040] In an advantageous further development the drive input shaft canif necessary be separated from a drive motor by a coupling element, andas that coupling element a hydrodynamic converter, a hydraulic clutch, adry starter clutch, a fluid starter clutch, a magnetic powder clutch ora centrifugal clutch can be used.

[0041] Such a starting element can also be arranged after thetransmission, and in that case the drive input shaft is in fixedconnection with the crankshaft of the engine. According to theinvention, starting can also take place by means of a shift element ofthe transmission, preferably by means of the brake 04, the brake 03 orthe clutch 16.

[0042] The multi-stage transmission according to the invention alsoenables a torsional oscillation damper to be arranged between the engineand the transmission.

[0043] In a further embodiment of the invention (not illustrated), awear-free brake can be arranged on any shaft, preferably in the driveinput shaft or the drive output shaft, and this is of particularimportance especially for use in goods vehicles. An auxiliary driveoutput can also be provided on any shaft for driving additionalaggregates.

[0044] The shift elements used can be made as change-under-load clutchesor brakes; however, disk brakes, band brakes and/or conical clutches canalso be used. Furthermore, form-enclosing brakes and/or clutches such assynchromesh or claw clutches can be used.

[0045] A further advantage of the multi-stage transmission proposed hereis that an electric machine can be connected to any shaft as a generatorand/or as an additional drive.

[0046] Clearly, any design structure and in particular any spatialarrangement of the planetary gearset assemblies and shift elements intheir own right and relative to one another, provided it is technicallyappropriate and does not affect the function of the transmission asindicated in the claims, falls under the protection scope of the presentclaims even if the said structures are not explicitly indicated in thefigures or the description.

Reference Numerals

[0047]0 Shaft

[0048]1 Shaft

[0049]2 Shaft

[0050]3 Shaft

[0051]4 Shaft

[0052]5 Shaft

[0053]6 Shaft

[0054]03 Brake

[0055]4 Brake

[0056]5 Brake

[0057]6 Clutch

[0058]15 Clutch

[0059]16 Clutch

[0060] P1 planetary gearset

[0061] P2 planetary gearset

[0062] P3 planetary gearset

[0063] An Drive input

[0064] Ab Drive output

[0065] i Transmission ratio

[0066] φ Speed change

1. Multi-stage transmission of planetary structure, in particular for amotor vehicle, which comprises a drive input shaft and a drive outputshaft arranged in a housing, three single-web planetary gearsetassemblies (P2, P2, P3), at least six rotatable shafts (0, 1, 2, 3, 4,5, 6) and at least five shift elements (03, 04, 13, 15, 16) whichconsist of brakes and/or clutches, whose selective engagement two at atime produces various transmission ratios between the drive input andthe drive output shafts so that six forward gears and one reverse gearcan be engaged, characterized in that the drive input shaft (1) isconnected via the clutch (15) to the solar gear wheel or the web of thefirst planetary gearset (P1), the web or solar gear wheel of the firstplanetary gearset (P1) is in rotationally fixed connection with thehousing, the drive output takes place via a shaft (2) which is connectedto the annular gear wheel of the second planetary gearset (P2) and tothe web of the third planetary gearset (P3), a shaft (3) is permanentlyconnected to the web of the second planetary gearset (P2) and to theannular gear wheel of the third planetary gearset (P3), a shaft (4) ispermanently connected to the solar gear wheel of the second planetarygearset (P2) and to the annular gear wheel of the first planetarygearset (P1), a shaft (5) is permanently connected to the solar gearwheel or web of the first planetary gearset P1), and a shaft (6) ispermanently connected to the solar gear wheel of the third planetarygearset (P3), such that the shaft (3) can be coupled to the housing by abrake (03), the shaft (4) can be coupled to the housing by a brake (04),a clutch (13) connects the shafts (1) and (3) to or releases them fromone another, a clutch (16) connects the shafts (1) and (6) to orreleases the from one another, and a clutch (15) connects the shafts (1)and (5) to or releases them from one another.
 2. Multi-stagetransmission of planetary structure, in particular for a motor vehicle,which comprises a drive input shaft and a drive output shaft arranged ina housing, three single-web planetary gearset assemblies (P2, P2, P3),at least six rotatable shafts (1, 2, 3, 4, 5, 6) and at least five shiftelements (03, 04, 05, 13, 16) which consist of brakes and/or clutches,whose selective engagement two at a time produces various transmissionratios between the drive input and the drive output shafts so that sixforward gears and one reverse gear can be engaged, characterized in thatthe drive input shaft (1) is connected directly to the solar gear wheelor to the web of the first planetary gearset (P1), the web or solar gearwheel of the first planetary gearset (P1) can be put into rotationallyfixed connection with or released from the housing by a brake (05), thedrive output takes place via a shaft (2) which is connected to theannular gear wheel of the second planetary gearset (P2) and to the webof the third planetary gearset (P3), a shaft (3) is permanentlyconnected to the web of the second planetary gearset (P2) and to theannular gear wheel of the third planetary gearset (P3), a shaft (4) ispermanently connected to the solar gear wheel of the second planetarygearset (P2) and to the annular gear wheel of the first planetarygearset (P1), a shaft (5) is permanently connected to the web or to thesolar gear wheel of the first planetary gearset (P1), and a shaft (6) ispermanently connected to the solar gear wheel of the third planetarygearset (P3), such that the shaft (3) can be coupled to the housing by abrake (03), the shaft (4) can be coupled to the housing by a brake (04),a clutch (13) connects the shafts (1) and (3) to or releases them fromone another, a clutch (16) connects the shafts (1) and (6) to orreleases them from one another, and the brake (05) connects the shaft(5) to the housing or releases it therefrom.
 3. Multi-stage transmissionaccording to claim 1, characterized in that the fixed connection of theannular gear wheel of the first planetary gearset (P1) to the housingcan be replaced by a releasable connection by means of a brake. 4.Multi-stage transmission according to claim 3, characterized in that anelectric machine or another suitable additional drive machine can bearranged on the shaft (0) associated with the housing.
 5. Multi-stagetransmission according to any of claims 1 to 4, characterized in thatthe first planetary gearset is formed as a positive planetary gearsetand the second and third planetary gearset (P2, P3) as negativeplanetary gear sets.
 6. Multi-stage transmission according to any of thepreceding claims, characterized in that freewheels can be inserted atany suitable point of the transmission.
 7. Multi-stage transmissionaccording to claim 6, characterized in that the freewheels can beinserted between the shafts (0, 1, 2, 3, 4, 5, 6) and the housing. 8.Multi-stage transmission according to any of the preceding claims,characterized in that the drive input and the drive output are providedon the same side of the housing.
 9. Multi-stage transmission accordingto any of the preceding claims, characterized in that the drive inputand drive output are provided on opposite sides of the housing. 10.Multi-stage transmission according to any of the preceding claims,characterized in that an axle differential and/or a transferdifferential is arranged on the drive input side or on the drive outputside of the housing.
 11. Multi-stage transmission according to any ofthe preceding claims, characterized in that the drive input shaft (1)can be disengaged from a drive engine by a coupling element. 12.Multi-stage transmission according to claim 1 1, characterized in thatas the coupling element, a hydrodynamic converter, a hydraulic clutch, adry starter clutch, a liquid starter clutch, a magnetic powder clutch ora centrifugal force clutch is provided.
 13. Multi-stage transmissionaccording to any of the preceding claims, characterized in that in theforce-flow direction an external starting element is arranged after thehousing, in particular according to claim 12, such that the drive inputshaft (1) is in fixed connection with the crankshaft of the driveengine.
 14. Multi-stage transmission according to any of the precedingclaims, characterized in that starting takes place by means of a shiftelement of the transmission, and the crankshaft of the engine ispermanently connected to the drive input shaft (1).
 15. Multi-stagetransmission according to claim 14, characterized in that the brake(04), the brake (03) or the clutch (16) can be used as the shiftelement.
 16. Multi-stage transmission according to any of the precedingclaims, characterized in that a torsional oscillation damper can bearranged between the engine and the transmission.
 17. Multi-stagetransmission according to any of the preceding claims, characterized inthat a wear-free brake can be arranged on any shaft.
 18. Multi-stagetransmission according to claim 17, characterized in that a wear-freebrake can be arranged on the drive input shaft (1) or on the driveoutput shaft (2).
 19. Multi-stage transmission according to any of thepreceding claims, characterized in that an auxiliary drive output can bearranged on any shaft to drive additional aggregates.
 20. Multi-stagetransmission according to claim 19, characterized in that the auxiliarydrive output can be arranged on the drive input shaft (1) or on thedrive output shaft (2).
 21. Multi-stage transmission according to any ofthe preceding claims, characterized in that the shift elements areformed as change-under-load clutches or brakes.
 22. Multi-stagetransmission according to claim 21, characterized in that disk clutches,band brakes and/or conical clutches can be used.
 23. Multi-stagetransmission according to any of the preceding claims, characterized inthat form-enclosing brakes and/or clutches are provided as shiftelements.
 24. Multi-stage transmission according to any of the precedingclaims, characterized in that an electric machine can be connected toany shaft as a generator and/or as an additional drive machine.